1. Field of the Invention
This invention relates to a surgical instrument for remote manipulation and more particularly to an instrument for use in endoscopic surgery, the instrument having an articulated shaft and transmitting rotational motion to the distal end of the instrument.
Minimally invasive surgery (MIS) such as laparoscopic, endoscopic, hysteroscopic, and arthroscopic surgery (referred to hereafter generally as endoscopic surgery), is becoming more widely used because it is less traumatic to the patient, generally involves less hospitalization time, less discomfort and less risk to the patient, and is usually less costly than traditional open surgery.
Such a procedure is typically performed by making a small incision in the patient which provides access to the area to be treated. A trocar sheath may be inserted in the incision and an airtight seal around the trocar established. The area under the skin which is to be treated may be dissected from surrounding tissue by, for example, balloon dissection. With or without dissection, the area may be expanded slightly as by insufflation with CO.sub.2 in order to create a cavity within which to perform the surgical procedure. Access to this cavity may be through by one or more trocar sleeves which may be configured to permit the slidable insertion of endoscopes and surgical instruments without compromising the air tight seal around the trocar sheath. Each such endoscopic surgical instrument is often inserted through a different incision.
The endoscopic surgery is generally preformed using elongate instruments slidably inserted through the trocar sleeves, or if the endoscopic surgery is performed in a naturally occurring body cavity, such as the uterus, the instruments may be inserted through a relatively narrow body orifice such as the cervix. The manipulations being performed by the instruments during endoscopic surgery are generally observed through an endoscope which may be inserted through a separate trocar into the operating cavity. Alternatively, the endoscope may be contained within a surgical tube which also contains surgical instruments. In any event, the operator must perform the surgical manipulations using an effector unit, such as a scalpel or needle gripper on the end of the surgical instrument remotely located from the operator's hands and confined within a relatively small cavity created for the operation. The manipulation must be performed while observing the procedure with an endoscope. The image from the endoscope is often displayed on a video screen and generally results in an image having little or no depth perception.
Of particular interest is suturing or tying knots during endoscopic surgery. Suturing and tying knots using remote effector units while observing the manipulation through an endoscope is very challenging for the surgeon. Traditionally the surgical instruments employed to perform endoscopic suturing may include simple endoscopic needle holders, a variety of specialized needle drivers, and motorized telesurgical systems. The problems associated with remote knot tying have lead to the development of such instruments and devices as pre-tied knots, ultrasonic welded knots, beads swaged in such a way as to facilitate the crimping of sutures together, and, again, motorized systems. Most of the methods described above are limited in use to interrupted rather than continuous suturing. Some, for example the telesurgical system, require complex instrumentation and may not be available for all endoscopic procedures, especially the simpler procedures. In addition, the motorized systems generally limit or eliminate the kinesthetic ability of the surgeon to sense and directly manipulate the suture or needle.
One particularly cumbersome technique that is often used to achieve suturing using traditional endoscopic instruments, is the "hand off" of the needle from one instrument to another. This technique exacerbates the difficulty of remote manipulation in limited space and restricted visualization with the requirement of coordination of two or more instruments. This technique involves insertion of the suturing needle by the operative instrument into the tissue to be sewn. The needle is then pushed forward, driving the needle through the tissue. A second instrument, may apply counter-pressure to the tissue at the location where the sharp tip of the needle will emerge at the end of the stitch. This entrance drive of the needle through the tissue generally involves a rotating motion, particularly critical where a sharply curved needle is used.
Once the tip of the needle emerges from the tissue, it is extracted by the assisting instrument grasping the tip of the needle and pulling. The principal needle driver releases its grip on the needle and may be placed beside the location where the needle is exiting the tissue to act as a counter-pressure instrument in place of the assisting instrument which is now pulling the needle from the tissue, pushing the tissue down while the needle is being pulled out by the assisting instrument. As with the entrance drive, the extracting motion often involves significant rotation in order to avoid tearing the tissue, particularly with a sharply curved needle.
After the needle is extracted, the trailing suture may be pulled through the tissue, again with the use of two cooperating instruments, each pulling at the suture sequentially until the correct amount of suture has been pulled through the tissue.
For single stitch technique, the suture is then tied, itself a complex procedure especially where performed with a viewing system having very limited depth perception. When continuous sewing is performed, the needle is grasped by the principal operative instrument after the suture is pulled through the tissue as desired in preparation to performing the sequence again to form a second stitch. First, the assisting instrument grasps the fully extracted needle and holds it in an optimal position for the principal needle driver to grasp. The assisting second instrument generally must grasp the needle near the tip so that the principal needle driver can grasp the needle far enough to the rear of the sharp tip to provide adequate length to pass the needle through the tissue layers during the next entrance drive so that enough of the needle tip will exit to be grasped by the assisting instrument. The assisting instrument must hold the needle at an appropriate orientation so that the principal needle driver will grasp the needle at the proper orientation for making the next entry into the tissue. Since traditional endoscopic instruments have a limited range of rotation at the distal end relative to the handle, this orientation is critical. Once again, this needle insertion and drive through the tissue, and subsequent extraction of the needle at the end of the stitch, requires significant rotational motion. It is often desirable during such procedures to hold the forearms of the operator relatively stationary, the rotational motion imparted by the hands of the operator rotating at the wrists may be insufficient to successfully accomplish the stitching.
The efforts required for a successful hand-off and continuous suturing highlights a number of problems with current endoscopic tools. It is a problem to properly orient the needle relative to the needle gripper. For effective suturing, the curved needle should be grasped by the principal needle driver with the needle extending perpendicular to the grasper and with a sufficient length of the front end of the needle protruding so that the needle may be inserted into the tissue. This is very difficult when the operator is viewing the procedure with limited or no depth perception.
It is also a problem to provide sufficient rotation after grasping the needle to rotate the needle to insert the tip into the desired location to start the stitch. This is particularly problematic given the limited rotational motion of the human wrist, or with mechanical devices such as side mounted rotational knobs that are sometimes provided to achieve rotation at the distal end at an endoscopic tool. The requirement for two instruments to carry out this technique may also create the need for additional incisions, further complicating the procedure and adding additional trauma, risk and expense to the procedure.
Another problem presented by the use of some current endoscopic instruments with needle grabbers is access to a location that is at an angle to the end of a straight surgical instrument. An endoscopic surgical instrument must generally be straight to be inserted through a trocar sleeve. Although some angle of reach is available by twisting the trocar in the patient's body and thereby pointing the instrument in slightly different directions, this is obviously limited by such considerations as the need to keep the trocar incision relatively airtight if the operating cavity is insufflated, and the need to avoid traumatizing the patient unnecessarily. Since movement of the instrument and the twisting and straining of the trocar at the site of the incision can threaten the airtight seal and be traumatic to the patient, it would be preferable to reach locations within the operating area by articulating the end portion of the surgical instrument without having to twist the instrument or the trocar at the site of the incision. Some form of articulation within the instrument shaft, preferably near the distal end of the instrument shaft, with the articulation being controllably adjustable by the operator after insertion of the instrument, is advantageous.
Various endoscopic surgical instruments, such as surgical staplers, and surgical retraction devices for use in endoscopic procedures, are disclosed in the prior art. See, for example, U.S. Pat. No. 5,192,288, directed to a surgical clip applier and U.S. Pat. No. 5,431,669, directed to a surgical clip applier with distal hook. Also disclosed in the art are endoscopic surgical instruments having knobs for the adjustment of angles of articulation and rotation of a staple applier as disclosed in U.S. Pat. No. 5,662,662, directed to a surgical instrument and method, and U.S. Pat. No. 5,607,095, directed to an endoscopic surgical instrument with pivotable and rotatable staple cartridge.
Graspers for suture needles are also shown in the prior art. For example, U.S. Pat. No. 5,015,250, directed to a medical instrument for driving a suture needle, discloses a needle driver instrument suitable for use with a trocar sheath in operative endoscopic surgical procedures for holding and driving a curved suture needle.
Given the needs of those operating in the environment of endoscopic surgery, it would be desirable to provide a surgical instrument directly responsive to hand and forearm rotation which is capable of imparting rotational motion in a non 1:1 ratio to an effector unit such as a needle gripper. It would also be desirable to provide a needle gripper which would automatically orient a curved suture needle. Additionally, it would be desirable to provide a needle gripper which could be remotely operated by, for example, operating a reciprocating rod at the handle of a surgical instrument to open and close the jaws of a needle gripper at the distal end of an elongate shaft on the surgical instrument. Moreover, it would also be desirable to provide a surgical instrument such as a needle gripper that could simultaneously be manipulated in multiple ways, such as opening and closing and simultaneously rotating, by the same hand of the operator, thus providing dynamic control over the manipulation of effector unit such as a needle gripper.